1. Material acceptance and storage
Pipe inspection:
Check whether the specifications (such as 25mm HDPE pipes) meet the design requirements
Check whether the pipe body has scratches, dents or bubbles
Confirm that the pipe markings (SDR value, pressure level, etc.) are clear and complete
Pipe fitting preparation:
Prepare matching flanges, electric fusion sleeves, sealing rings and other connectors
Ensure that hot melt welding machines, cutting tools and other equipment are in good condition
Storage requirements:
Avoid direct sunlight and store in a cool and ventilated place
Stacking height should not exceed 1.5 meters to prevent deformation
2. Construction environment assessment
Measure the slope and elbow position of the installation line
Check whether the groove has reached the designed depth (usually the pipe diameter + 30cm)
Remove sharp stones and other debris in the groove that may damage the pipe.
1. Pipe cutting and processing
Use a special pipe cutter to ensure a smooth cut
Remove burrs and keep the port clean
Scrape the pipe ends that need to be hot-melt connected (remove the oxide layer)
2. Detailed explanation of the main connection methods
(1) Hot-melt butt connection
Heat the welding machine heating plate to 200-220℃
Push both ends of the pipe to the heating plate at the same time to apply pressure
After reaching the molten state, quickly remove the heating plate
Immediately press the two ends together and maintain pressure until cooling
(2) Electrofusion connection
Clean the pipe connection part
Insert the Electrofusion coupling and fix it
Turn on the power and weld according to the set parameters
Moving the pipe is prohibited during natural cooling
(3) Flange connection
Applicable to connection with valves, pumps and other equipment
Special HDPE flange joints are required
Bolts should be tightened evenly at the diagonal angle
3. Key points for pipeline laying
An expansion joint should be installed every 30 meters on the straight section
Use standard elbows at the bends and forceful bending is prohibited
A casing protection should be installed when crossing a building
1. Appearance inspection
No cold welding or burning at the connection parts
No abnormal deformation of the entire pipeline
The pipeline direction meets the design requirements
2. Pressure test
Slowly inject water to remove air
Rise to 1.5 times the working pressure and maintain pressure for 30 minutes
The pressure drop is not more than 0.05MPa to be qualified
3. Completion acceptance materials
Material qualification certificate
Welding process record
Pressure test report
Concealed project acceptance record
1. Leakage at the connection
Reason: Insufficient welding temperature/time
Handling: Re-weld after cutting
2. Pipe deformation
Reason: Insufficient compaction of backfill soil
Handling: Dig out and re-lay and compact in layers
3. Insufficient interface strength
Reason: Moving the pipe during cooling
Prevention: Fix after welding until completely cooled
Hot-melt operators need to wear protective gloves
Ensure stable power supply during electric melting connection
Slope support is required for trench excavation
Set up obvious warning signs in the construction area
1. Water supply pipeline
Need to be disinfected and flushed after installation
Use blue pipes for easy identification
2. Gas pipeline
Must use yellow special HDPE Natural Gas Pipes
Welders need to hold special operation certificates
3. Industrial pipeline
Choose the corresponding material considering the corrosiveness of the medium
May need to add protective sleeves
Warm reminder: This article is suitable for the installation of common 25mm-400mm HDPE pipes. Extra-large pipes require special construction processes. It is recommended that professional construction teams be used to ensure the quality of the project.
